The reason everyone underestimates Facebook is that the company is putting up such massive numbers — 1.3 billion monthly active users and nearly $3 billion in quarterly revenue. It is sometimes hard to appreciate just how truly massive Facebook is.

In reality, Facebook is probably even bigger than you think it is. The company actually has more than 2.2 billion monthly active users (MAUs) across its flagship properties:

Facebook has 1.3 billion MAUs.

WhatsApp has 500 million MAUs.

Instagram has 200 million MAUs

Messenger has 200 million MAUs.

Total users: 2.2 billion

A year ago, Facebook reported 1.1 billion users and a few dozen million on Instagram. So the total Facebook Inc. user base has roughly doubled in a year. (Of course, many of these users are overlapping their use of more than one app.) But still — it's huge. It's the equivalent of nearly one in three of all the human beings on Earth.